TULSA, Oklahoma (CNN) -- Weeks of protests, rallies, lawsuits and candlelight vigils failed to stop a new state immigration bill -- HB 1804 -- from becoming the law in Oklahoma.

Vigils like this one in Tulsa, Oklahoma, last week were unable to stop a tough new immigration law.

The law went into effect Thursday and is intended to make life difficult for illegal immigrants in Oklahoma.

Its authors say they're sending a very clear message: If you're an illegal immigrant, you are not welcome.

"I'm convinced illegal aliens will not come to Oklahoma, or any other state, if there are no jobs waiting for them." said state Rep. Randy Terrill, a Republican and the law's author.

"They will not stay here if there are not taxpayer subsidies and they certainly won't stay here if they ever encounter one of our fine state and local law enforcement officials," he added. "They'll be physically detained -- until they're deported."

The new law restricts the ability of illegal immigrants to obtain government IDs or public assistance. It also gives police authority to check the immigration status of anyone arrested, which can lead to deportations.

It doesn't stop at illegal immigrants. The law also makes it a felony for U.S. citizens to knowingly provide shelter, transportation or employment to illegal immigrants.

The message has been received loud and clear. Many in Oklahoma's Latino community say people are staying home, fearful police will arrest and deport them.

"They're afraid they're going to get deported. They're just afraid," said Alex Yoguez, a juice store owner who relies on Latino customers for her business to survive.

Yoguez said her business is normally filled with customers. "We are down 50 percent just today," she said Thursday, the day the law went on the books.

Latino supporters are up in arms about the way the state now views illegal immigrants who have been here for many years.

"You are guilty of ethnic cleansing in this community! You are going against my community!" said the Rev. Miguel Rivera of the National Coalition of Latino Clergy.

The clergy group filed a federal lawsuit against the state saying the state has overstepped its bounds by enforcing immigration law, which is under federal jurisdiction. A hearing in the case is scheduled next week. An earlier attempt to get an injunction to prevent enforcement of the law was turned down by a judge.

It's not yet clear how the law will be enforced. Illegal immigrants in Oklahoma fear police will use the law for roundups of anyone working and living in the state illegally.

"I don't know if we're going to be actively looking for them," said Tulsa Police Capt. Steve Odom, who works in the Latino district of Tulsa. "If we come across them in the course of a call, or a course of an investigation, certainly we'll take the appropriate action."

The Tulsa Police Department said it has not received guidance from the district attorney's office on how to enforce the law. The department points out that suspicion of illegal activity is not enough, and proving the intent of U.S. citizens is a challenge.

Still, many in Oklahoma say Latinos have been leaving by the thousands since the law was passed in May.

"We are losing a lot of business, a lot of business," said Antonio Perez, who owns Mexican grocery stores. "I would say between the four stores we have lost about $300,000 a month in sales."

So far, the absence of the Latinos on the streets may be the only visible result of the law.E-mail to a friend